Engine blower drive and control



- Jan.;25,1938. l E. s. BUSH 2,106,237

I ENGiNE BLOWER DRI VE AND CONTROL Filed Fb'. 4,- 1935 Sheefts-Shet 1 w J0 Y a 27 I 493 7 J7 1. 42

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, ATTORNEY,

Jap. 25, 1938. 5 s. BUSH ENGINE BLOWER DRIVE AND CONTROL I Filed Feb. 4, 1935 Ill Armm- Jan. 25, 1938. E. s. BUSH Brianna 31.0mm DRIVE AND com-Ron Filed Feb.,4, 1935 ssnafi-smz a INVENTOR. [WE/V5 5.13115- Arron/5y.

Jan, 25, 1938.

E. s BUSH ENGINE BLOWER DRIVE AND CONTROL Filed Feb. 4, 1935 5 Sheets-Sheet 4 I -INVENTOR.' 'EUGENE $5031 1. WM? I 'ATTO} EY.

E. s. BUSH ENGINE BLOWER DRIVE AND CONTROL Jan. 25, 1938.

FiledFeb. 4, 1955 s Sheets-Sheet 5 l: Ill- I N VEN TOR. file/5N5 SBuSH I I Arron NZ Patented Jan.-

PATENT OFFICE 2,106,237 ENGINE BLOWER AND CONTROL I Eugene S. Bush, St. Louis, Mo., assignor to Bush ufiwturing' Company, corporation of Missouri St. Louis, M0,, a

Application February 4, 1935, Serial No. 4.742 s (01. 230-116) .This invention relates to improvements in engine blower drives and controls, and particularly to an automatically-variable drive assembly for use in combination with aircraft engines of internal combustion type.

. The present tendency toward and improved facilities for commercial flying at higher altitudes,

has'accentuatedgthe necessity for an automatic control of engine air input. for example, as by .a supercharger, commensurate with the increased range ofaltitudes encountered. Thepresent substantial number of controls and instruments and the demands thereof upon the pilots attention and time, dictate the advisability of a reliable automatic control of as many control elements as possible. In-the fulfillment of this existing demand, the present invention'has its general object.

The usual practicein prevailing types of aircraft engines is to employ. for normalizing the pressure of air supplied to the engine at appreciable altitudes, a centrifugal supercharger driven directly from the engine, or through the agency of a train of. gears. In the absence of speed-change provisions, it isobvious that, say at w a constant cruising speed, the mass of air delivered by thesupercharger is reduced with increase in altitude of the aircraft;

Speed change transmissions of usual type are inadequate for several reasons, principally be cause of excess weight and space requirements, and further because of the restricted number of definite speed ratios afforded by any equipment presently and practically available.

The present invention seeks objectively to avoid these difiiculties by providing for the driving of an engine blower, such as a supercharger, through an automatic speed-change device which is susceptible of infinite variation in the speed ratios therethrough, between predetermined limits.

Yet anotherobject of the-invention is attained in an improved mechanical power transmission unit particularly adapted for the purpose noted,-

but susceptible of other uses, and through which an infinite number of ratios maybe attained between upper and lower limits.

A still further object .of the invention is attained, in a device of the general type noted, in the provision of rotatable drive elements of infinitely variable diameter between limits, but

susceptible of controlled change in diameter,and hence in drive ratio, while in operation.

An additional object of the invention is attained in a supercharger drive of the type referred to,- which is capable of extremely high speed opera-2 tion, and in which provision is made'forobviating .adverse shearing stresses incident to the torque j in connection with an aircraft engine, this object including an improved method'of assuring, independently of the personal equation, a constant coordination of theisupercharger drive speed, with fluctuations in ambient air pressure.

A still further objectisattained in improved means for electrically energizing the. control of a variable speed supercharger in response to variations in ambient air pressure.

The foregoing and still further objects will clearly appear from ,the following detailed description-of certain preferred embodiments of the invention, and from the accompanying drawings,

in which:

Fig. 1 is avertical sectional elevation throughcertain of, the power transmission elements and rotor of a supercharger embodying features of the-present invention; Fig. 2 is a vertical transverse section of the assembly of Fig. 1, as viewed along line 2-2 thereof; Fig; 3 is a transverse sectio'nal elevation of certain of the drive elements, asviewed along line 33 of Fig. -1; Fig. 4 is a fragmentary elevation in perspective, illustrating certain structural details of one of the variablediameter power-transmission elementsv of the charger drive; Fig. 5 is a fragmentary structural detail shown in vertical sectional elevation, be-

craft engine of radia type, in combination with which the features of the present invention are utilized; Fig. 8 is a vertical sectional elevation, corresponding to Fig. 1, but showing only the lower half of the casing containing'the' drive ele- 5 ments, and illustrating a modified arrangement of control parts; Fig. 9 is'a fragmentary sectional elevation of certain ofthe control elements of Fig. 8, shown in a-difierent position; Fig-10 is a view partly in section -and partly'in elevation, taken along a staggered plane identified with line Illill of- Fig. 8; Fig. 11 is a view, partly structural andpartly diagrammatic, of a modified form of electrical .control adapted for use with the systern to be described, and Fig. 12 is a lateralsec- Referring now by characters of reference to the drawings, there is shown by Fig. '1 an aircraft engine, indicated generally at j 5, of radial type. The engine cylinders, one of which. is shown at l5, each serves operatively to contain a power piston l1, while a crank 18 serves through the agency of a rod I! to supply power to the crankshaft 20, to which may be secured the usual propeller hub or boss (not shown). There is shown as located rearwardly of the engine a car- 'buretor 2|, the air intake of which issupplied from a discharge duct (not shown) of a supercharger, the impeller of which is indicated at 22 and the'volute or casing of which appears at 23. Air is supplied from a duct 24 which serves to receive air at ambient pressure, whence it is directed to the central area of the impeller. As will be understood, the air is discharged peripherally by the impeller 22, through the volute 23 whence it is directed at a volume and pressure proportionate to the impeller speed, into the carburetor and/or manifold of the engine.

The rear end of the engine crankshaft 25 is provided with a cupped recess 25 (Fig. 5) preferably formed to receive, and in part to constitute an overrun clutch which may be of the type shown by Figs. 5 and 6. The external element of this clutch is shown as a projection 25 on the crankshaft, while the internal element, shown at 21, is peripherally recessed to receive a plurality of rollers 28, each urged by a coil spring 28into wedged driving position between the elements 25 and 21.. The inner element 21 of the overrun clutch is internally splined as at 30 to accommodate corresponding e'xternal splines 3| on a stub shaft 32 of the variable speed drive gear assembly. The splined arrangement, as will appear, permits easy assembly and removal. of the supercharger drive structure, for service or repair purposes.

The shaft 32 continues into a journalled portion of reduced diameter (Figs. 1 and 5) which is mounted in ball bearings 33, this shaft projecting beyond its journalled portion for the reception of a gear 34. This gear and shaft portion are keyed or otherwise fixedly secured together and contained within a detachable case section 35 which serves also to house a plurality of pinions 35 (Figs. 1 and 3), each of these pinions being in operative engagement with the gear 34 and each keyed or otherwise secured to a shaft 31. 1

The several shafts 31 are or may be uniform as to arrangement and appurtenances so that a description of one, say the upper such shaft, will suffice for a description of all thereof. The upper shaft 31 is journalled in the casing or housing 38 (Figs. 1. and 7), through the agency of ball or other anti-friction bearings 39. The shaft 31 further serves to carry a pair of hub struc tures such as 48 and 4|, the hub 4|) being, by preference, fixedly positioned axially of the shaft as by a threaded collar42, while the opposite corresponding element is axially displaceable along the shaft while rotatably secured thereto, as by splines 43 on the shaft, engaging corre-. sponding'splines internally of the hub element 4|. A coil spring 44 of compression type abuts the outer end of the hub structure 4| and engages the ball bearing structure 39 at its opposite end. A pair of collars 45 on the hub. structure 4|, and 45 on the structure 48, are kept in assembly respectively by a threaded collar 41 and the threaded collar 42, the collars 45 and 45 each being provided with and serving as abutments for a plurality of spacers 48, best shown by Fig. 4, the spacers being secured to or formed as parts of the associated collar, such as 45 or 45 and coacting therewith to position a plurality of pivot elements 49. To each of these pivots is connected a link 50, these links being, in turn, pivotally connected as at 5| to the opposite ends of a drivingelement 52 extending to theperiphery of tion of the segments 52 to the hub elements 41 and'40, provides a rotatable power transmission wheel of variable diameter, and available with similar coacting elements for varying the speed ratio through the assembly to any desired gree between limits. 1

As will best appear from Figs. 2 and 3, my pref: erence is to locate the several shafts 31 in fixed parallelism and balanced relation, as at equal angles about an intermediate or driven shaft 55. This shaft isjournalled in the opposite walls of the housing 38 as by antifriction bearings55, and is provided, rearwardly. of the housing, with an extension 51 towhich is secured, as by a key a 58, the impeller 59 of the blower, or some equivalent fluid displacement element. The shaft 55 is provided on an end portion relatively opposite to the shafts 31, with a splined zone 55, and

serves further to carry a variable-diameter drive structure, the corresponding elements of which bear the same reference numerals as those carried by the several shafts 31. It will, however, be noted that a relatively opposite hub element of the assembly on shaft 55 is axially movable, and that a spring 5|,is located at the opposite end of the assembly relative to the spring 44, with the result that the springs 44 and 5| are oppositely loaded.

It is my preference to provide for control of the variation in relative diameters of the variable-ratio power transmission elements on the shafts 31 and 55, through an axially movable colgagement with a pivoted arm 55 provided with a sleeve end for telescopically receiving the member 55, and also containing a spring 51 tending to urge the rod 55 into controlling engagement with the collar 52. The arm 55 is pivoted as at 58 to a bracket '59 carried by the adjacent wall of the case 38. It is my preference to extend the pivot 58 to a point exteriorly of the casng 38, for the reception of an arm 10 (Fig. '7), to which may be pivotally secured a control rod 1| extending to a convenient point of manual access, say an instrument board in the control cockpit.

The provision of a manual control is optional, as will appear, it being my preference to provide tive diameters of the drive structures on shafts 31 and 55. It may here be notedthat the maximum diameter of each of the variable transmission members is determined according to the abutting positions'of the companion hub structures thereof, while the minimum diameter, sub- 'stantially as the central element appears in Fig. 1, is determined by the outermost possible position of the collar 02, providing a maximum spac- It may ing of the associated hub structures. further be noted that in this position, as ap-' pears in Fig. 2, the peripheral segments' 52 are in lateral adjacence to each other, and so provide a continuous periphery, while the spacing of the peripheral segments in the position of greatest diameter is preferably such as not to exceed the peripheral width of the individual segments,

As a means for automatically controlling the speed ratio through the drive illustrated by Figs. 1 and 2, there is shown a vacuum or aneroid casing, preferably formed of metal, the bottom and side walls of which are indicated at 12 and 13 respectively, and the upper wall 14 of which constitutes a flexible diaphragm. Secured cen- ,trally of this diaphragm, or at a position to be imparted'the maximum, movement thereof responsive to changes in ambient pressure, is a post 15, pivotally connected as at 16 to a link 11 which is, in turn, pivoted by a pin 10 to a speed, it becomes apparent that a reduction in the ambient air pressure due to changes in altitude, will automatically fiex the diaphragm 14 outwardly, so as to reduce the diameter of the variable driving wheel of shaft and correspondingly to increase the diameter of the elements on each of shafts 31, thereby increasing the speed of the impeller 50, and tending-closely to maintain a constant pressure to the carburetor or intake manifold of the engine irrespective of altitude or other changes in barometric pressure. Ob-' viously, an opposite movement of the diaphragm and other control elementswill occur in response to an increasein presusre, due, say, to a loss of altitude.

It will have been observed that the variable drivewheels of Figs. 1 and 2 are easily'susceptib le of change in diameter while the device is in operation, and that during such period the oppositely acting and loaded springs 44 and BI serve to maintain the friction elements 53 of the coacting wheels, in frictionally engaging relation. It will further appear that, due to the opposite and substantially equal loading of the springs 44 and GI, the requirement of control energy for effecting changes in the relative diameter of these members is quite small, and hence in many instances, may be cared for by constructing the diaphragm and diaphragm chamber of a size not prohibitive from the point of view of aircraft space require-. ments. When, however, it is desired because of space or other restrictions, there may be operatively interposed in the control system, an independent sourceof energy, exemplified according to the modification of Fig. 8, by the use of 'an electromagnetic structure consisting of a sole; noid having a tubular core upon which is wound the number of ampere-turns of conductor 86, requisite to provide the desired flux. The core 05 is supported at one end as by a fibre or other insulating block 01, detachably secured as by cap screws 08 to a wall of the case 80.- A rod 00 serves as a guide for slidably receiving the movable core or armature of the solenoid, the'armaturebeing provided with a tubular extension SI, carry- 'ing' trunnions 92 engaged by the forked, end of the control rod 93, this rod being telescopically received ,by one of the paired hollow ends of a lever 94 pivoted at 95 to'a stationary bracket 06. At the opposite end of the pivoted element 94', is telescopically received an arm 01 which engages the axially movable collar 62' described in connection with Fig.. 1.

It will appear as desirable to provide for an infinite degree of variation in the diameter of the rotatable element carried by shaft 55-, and-hence a corresponding inverse variation inthe companion variable ratio elements carried by the shafts 31. According to the modification shown .by Figs. 8 10, an aneroid casing I00 provided with an outer wall in the nature of a diaphragm IN, is

mountedfon a vertical wall of the case 30, the diaphragm IOI being connected through a post I02 and a pivoted slot-and-pin connection I03 to a lever I04. This member is so pivoted at I05v to a stationary arm I06, that the short end of the lever'is connected to the diaphragm. The opposite end pivotally engages, through a slot-andpin connection I01, a contact'slide I00, the slide being movable from end length of the'solenoid.

The slide I00 serves to carry a. pair of diato" end of the wound k metrallyopposed and endwise spaced contacts I00 and I I0, which directly engage baredportion's of the winding 86. Contacts I00-I I0 are energized through conductors III, each secured at its opposite end to a binding post 2, the posts being in sliding circuit relation with conductor rods I I3 connected to a suitable source of supply (not shown). The rods I I3 are conveniently mounted along and laterally of the coil, so as guidingly to support the insulating body constituting the slide element I08.

From the foregoing it will appear that the solenoid is of constantly-energized type, and that 'any selected zone thereof may be energized, which is of an axial length equivalent to the longitudinal distance between the contacts I09 and I I0. It will further be seen that outward movement of the diaphragm "IOI will operate through lever- I04 to. move the slide I08, and hence the armature, to

to Y

the .right (Fig. 8) and in a direction to move the,

mines the zone of'energization of the electro-" magnet ina. manner to provide,- between limits, a practically infinite number 'ofdifferent speed ratios; further that practically any movement of the diaphragm IOI will result in a corresponding.

although multiplied movement of slide I08 and hence of armature or core 90. g

In Fig. 9 the controlelements described, particularly the armature, core and slide,.are shown in the relation they would-occupyat extremely reopposite to the preceding figures.

A slightly further modified agency for control of the solenoid is shown by Figs. 11 and 12 as adapted to a manual arrangement. In this arrangement the proximate turns of the winding II5 are not directly engaged by a contact slide, but are selectively and progressively energized for shifting the position of the armature I I6 and the control arm II! by 'a remote control agency. The several turns of conductor in proximate zones are connected in sequence toa row'or series of stationary contacts 8, the connections from these button contacts being made on one end of a stationary spider IISto turns near the right hand end (Fig. 11) while those on the right hand end of the quadrant or spider are connected to turns toward the opposite end of the solenoid core. The quadrant II9 serves to carry a pair of spaced arcuate. contacts I20 and I2I, the-former being engaged by a brush I22, and the latter by a brush I23 carried by an insulating portion I24 of a rotatable lever I25. The lever is shown as actuated by a control handle I25, pivoted at I21 to an extension I28 of the spider H9. The armate contacts I20 and I2I are connected through conductors I29 and I30 respectively, to a source (not shown) of electrical energy.

As will appear from Fig. 11, the course of the current may be followed, for example, from conductor I29 through the arcuate strip I20 and brush I22, through one of the buttons II8 into the core; from an opposite spaced turn or winding of the electromagnet the current is returned through a spaced button contact 8, thence through brush I23 to contact I2I and out through conductor I30. From this it will appear that movement of the lever I25, as by handle I26, will cause a progressive energization of the turns H5 of the solenoid in proximate zones thereof, so that the core. or armature H6 and hence the lever III, will be given a movement directly following that of the lever I25. The arrangement is such that, by using a sufficient number of turns II5 and a sufiicient number of the fixed contacts II8, the core is positionable in any zone between the end limits of its movement; otherwise expressed, the arrangement as employed for the control of an assembly such as that shown by stantial range of altitudes and ambient air pressures, it being understood that the described control of output of the engine charger or blower may be accomplished by other structural agencies than those described, and that the invention in its broader sense comprehends the method of engine operation, as well as thestructural embodiments or agencies by which the result is attained.

While the invention has been described by reference to certain exemplary embodiments thereof the foregoing is to be understood solely in a descriptive and not in a limiting sense, since numerous changes may be made in the parts; their duced air pressures, being the position relatively arrangement and their combinations, without departing from the full intended scope of the in- 1. In a drive and control assembly for a blower or the like, a variable speed transmission through which the blower is driven, a ratiovarying control member associated with the transmission, a device responsive to air pressure, an electromagnet in actuating relation to said control member, and control connections from the air-pressureresponsive device to the electromagnet.

2. In a drive and control assembly for a blower whose output is desirably variable according to air pressure, a variable speed driving device for the blower, a control member in speed-varying association with the device, an aneroid apparatus including an element movable responsively to changes in air pressure, an electromagnet in actuating relation to said control member, switching means associated with the electromagnet, and

a switch-actuating connection from the pressure I responsive element to the switching means.

3. The combination in a 'drive and control assembly for use with a supercharger or like device, of a variable speed transmission through which the driven device is operated, a speed-varying control member associated with the transmission, electromagnetic means in actuating relation to the control member, a device movable responsively to changes in fluid pressure, and switching means for the electromagnet operable in response to changes in the last said device.

4. Ina drive and control assembly for a supercharging blower or the like, a power transmission through which the blower is driven, the transmission being'of a type to provide a substantially infinite number of variations in drive ratio between practical upper and lower limits, a barometric control ior the transmission, an electromagnet in direct controlling relation with the transmission, and being of a type providing for minute control displacements, and switching means in circuit with the electromagnet device, and operable responsively to any substantial functional change in the barometric device.

5. In a drive and control assembly for a blower or the like, a variable speed tranmission, a ratiovarying control member associated with the transmission, a device having a portion movable in response to changes in air pressure, an electromagnet in actuating relation to said control member, a control connection from the pressureresponsive device to the electromagnet, and a balancing device for said control member, associated with the transmission and tending to equalize the energy for movement thereof incident to variation of transmission ratio.

6. In a drive and control assembly for a blower or the like, a variable speed transmission, a ratiovarying control member associated with the transmission, a barometrically responsive device, an ele'ctromagnet in actuating relation to' said control member, control connections from the barometrically responsive device to the electroassociated with the electromagnet, and a connec-,

through which theblower is driven, and being of a type providing for a substantially infinite number of speed ratios between practical upper and lower limits, a barometric device for establishing the transmission speed ratio, an electromagnet connected in speed-varying relation to the transmission, a movable contact member tion from the barometricdevice to the contact member.

8. In a drive and control assembly for a supercharger blower, a drive shaft, a transmission connecting the drive shaft to'the blower, the trans- 1 mission including a pair of coacting rotary members of inversely variable diameters, a pair of oppositely loaded spring elements coacting in.

tending to equalize the diameters of the coacting transmission elements, an'd tending to equalize the energy for 'efiecting ratio changes through the transmission, an electromagnet including a movable core, a reciprocable arm connecting the core. to the transmission for varying the relative V diameters of its elements, the electromag'net inair pressure, and a connection from said wall .po'r- 3 tion to the slide lever.

MEQUGENE s. BUSH. 

